|  | 3.1 | VLANs
| 3.1.1 | Existing shared LAN configurations
A VLAN is a logical grouping of devices or users. These devices or users can be grouped by function, department, or application, regardless of their physical segment location. VLAN configuration is done at the switch via software. VLANs are not standardized and require the use of proprietary software from the switch vendor. A typical LAN is configured according to the physical infrastructure it is connecting. Users are grouped based on their location in relation to the hub they are plugged in to and how the cable is run to the wiring closet. The router interconnecting each shared hub typically provides segmentation and can act as a broadcast firewall. The segments created by switches do not. Traditional LAN segmentation does not group users according to their workgroup association or need for bandwidth. Therefore, they share the same segment and contend for the same bandwidth, although the bandwidth requirements may vary greatly by workgroup or department.
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